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Arntsen A.E.,Dartmouth College | Song A.J.,ERDC CRREL | Perovich D.K.,Dartmouth College | Richter-Menge J.A.,Dartmouth College
Geophysical Research Letters | Year: 2015

The Arctic sea ice cover evolves dramatically through the summer melt season. Floe size distribution (FSD) is a critical parameter used to examine this change as the ice cover transitions from large rectilinear plates in spring to an ensemble of discrete rounded floes by midsummer. The FSD at a given time impacts the dynamic and thermodynamic behavior of the ice cover. Focusing on the seasonal marginal ice zone in the Beaufort and Chukchi Seas from May to September 2014, we present qualitative and quantitative results derived from National Technical Means high-resolution imagery and supported by ice mass balance buoy data. Results indicate that as melt accelerates, floe breaking pattern, and therefore FSD, is heavily influenced by the distribution of melt ponds. Discrete element model results using morphological conditions derived from analyzed satellite imagery confirmed that breaking occurs along ponds and perpendicular to applied stress. Key Points Floe size distribution in the marginal ice zone is heavily impacted by summer thermodynamics A network of mature melt ponds acts as linked perforations facilitating floe breakup in summer In the MIZ, FSD changes by the removal of thin floes due to surface and bottom melting © 2015. The Authors. Source


Ryerson C.C.,ERDC CRREL | Tripp S.T.,Randnter
Society of Petroleum Engineers - Arctic Technology Conference 2014 | Year: 2014

Superstructure icing occurs when spray freezes on offshore platforms and ships. Though superstructure ice accumulates fastest on moving vessels that generate bow spray, stationary structures also ice in storms. And ice from atmospheric sources also accumulates, affecting parts of platforms and ships not affected by sea spray. Icing is often accepted as an inconvenience to offshore operators, but that tolerance can reduce safety, operational tempo, and productivity. This report shows how to evaluate the impact of superstructure and atmospheric ice to offshore platform and ship functions and components from work conducted for the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), and for the US Coast Guard using questionnaires and observations. The report proposes a risk matrix approach for assessing the relative threat of ice from sea spray, frost, snow, rime and glaze to the safety and functions of platforms and ships, and demonstrates how to identify and prioritize areas requiring ice protection. It also briefly describes available ice protection techniques other than baseball bats and mallets. The goal is to provide a resource for offshore operators with superstructure icing-related safety concerns.Copyright 2014 Offshore Technology Conference. Source


Wagner A.M.,ERDC CRREL | Yarmak Jr. E.,Arctic Inc
ISCORD 2013: Planning for Sustainable Cold Regions - Proceedings of the 10th International Symposium on Cold Regions Development | Year: 2013

Migration of aqueous phase contaminants from underground tanks, nuclear waste sites, and in situ waste treatment areas into the groundwater is of concern at many locations. There is a wide range of technologies to remediate contaminated sites. Some examples are: constructed wetlands, air sparging, bioremediation, and permeable reactive barriers. One technology that has not been widely used is frozen soil barriers. The barrier provides containment of liquid contaminants in order to prevent their migration to adjacent areas. This is a promising method that is environmentally friendly and offers a safe alternative to other methods. Frozen barriers can be formed using a series of subsurface freezing pipes or probes. The installation of frozen barriers disturbs the existing ground minimally and only existing in-situ material is used. An artificial frozen barrier using hybrid thermosyphons was installed in Fairbanks, Alaska using six thermosyphons placed at a distance of 1.5 m. The system ran actively for about 60 days and operated in a passive phase during the winter months. A detailed description of the thermal performance of the barrier in Fairbanks from March through September will be presented. © 2013 American Society of Civil Engineers. Source


Kevern J.T.,University of Missouri - Kansas City | Zufelt J.E.,ERDC CRREL
ISCORD 2013: Planning for Sustainable Cold Regions - Proceedings of the 10th International Symposium on Cold Regions Development | Year: 2013

Over the past 20-30 years, permeable pavement installations have become wide-spread for stormwater control, especially in urban areas. A large amount of design guidance for permeable pavements exists in the literature; however, much of the guidance uses experience and case studies from warm regions. Permeable pavements have been successfully utilized in cold climates for stormwater management and often have ancillary benefits, such as reduced potential for slip and fall. ASCE's Technical Council on Cold Regions Engineering (TCCRE) has assembled the Permeable Pavements in Cold Climates monograph to address issues specific for freeze-thaw climates. The new for 2013 monograph brings together current industry best practices for designing, constructing, and maintaining permeable pavements with considerations specific to cold climates. This paper will provide an overview of the monograph and important areas of design, construction, and maintenance for pervious concrete, porous asphalt, and interlocking permeable pavements. © 2013 American Society of Civil Engineers. Source


Shoop S.A.,ERDC CRREL | Hills J.,Antarctic Support Contract | Uberuaga J.,Antarctic Support Contract
Proceedings of the International Conference on Cold Regions Engineering | Year: 2015

The snow roads at McMurdo Station, Antarctica, are the primary transportation corridors for moving personnel and material to and from the airfields servicing intra- and inter-continental air traffic. The majority of the road system is made of snow overlying a snow and ice subsurface. However, at the Scott Base Transition (SBT), the aggregate road leading from Scott Base transitions from the landmass of Ross Island on to the ice shelf and becomes a full depth snow road. Because of the transition between materials, the topography of the area, and extensive use during the austral summer, the SBT is prone to problems unique to that portion of the McMurdo road system and requires specific maintenance activities to remain passable during periods of high temperatures. The SBT area is divided into two subsections. One is the land transition, a soil- or aggregate-surfaced road underlain by permafrost, and the other is the ice transition, a snow-surfaced road underlain by snow and ice. The two sections of the SBT need entirely different construction and maintenance techniques to maintain road surface conditions that will support vehicle traffic. This paper presents some of the issues at the transition area along with maintenance and drainage control measures to alleviate them. © ASCE. Source

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